Quinestrol is a compound used in estrogen replacement therapy.

Quinapril Hydrochloride is an angiotensin-converting enzyme inhibitor. Quinapril is a prodrug that is converted to its active metabolite, quinaprilat. Quinapril’s target catalyses the formation of angiotensin II from its precursor, angiotensin I. Angiotensin II is a potent vasoconstrictor and thus preventing its formation causes vasodilation and an increased capillary blood volume.

Pyridostigmine Bromide is a cholinesterase inhibitor with a slightly longer duration of action than neostigmine. It is used in the treatment of myasthenia gravis and to reverse the actions of muscle relaxants.Pyridostigmine bromide binds reversibly to acetylcholinesterase active sites in the peripheral nervous system, thereby preventing the breakdown of acetylcholine. This leads to an accumulation of acetylcholine at cholinergic synapses and facilitates transmission of impulses across the neuromuscular junction.

Protriptyline Hydrochloride is a tricyclic secondary amine with antidepressant property. Protriptyline hydrochloride blocks the re-uptake of norepinephrine and serotonin by nerve terminals, thereby increasing available norepinephrine and serotonin. Protriptyline does not block dopamine transport but may have an indirect dopamine-facilitating effect through interactions of increased peri-synaptic abundance of norepinephrine, particularly in the cerebral cortex, where adrenergic terminals exceed dopaminergic terminals. This results in elevation of mood and behavioral activity. In addition, this agent exhibits anticholinergic activity.

Propantheline bromide inhibits action of acetylcholine at post-ganglionic synapses and acts as a muscarinic acetylcholine receptor antagonist, antispasmodic, and reduces gastric acid secretion. At high doses it has nicotinic effects resulting in neuromuscular blocking. Propantheline bromide competitively antagonizes acetylcholine activity mediated by muscarinic receptors at neuroeffector sites on smooth muscle and exocrine gland cells.

Propafenone Hydrochloride is a sodium channel protein inhibitor. Propafenone Hydrochloride is an inhibitor of AR.

Promethazine Hydrochloride is an antiemetic, antihistaminic, and CNS depressant. Promethazine Hydrochloride is a first generation histamine H1 receptor antagonist whose antihistamine activity. Promethazine can penetrate the CNS, depressing central H1-receptor activity, which may relate to its sedative properties, and can also inhibit muscarinic acetylcholine receptors.

Promazine Hydrochloride is a phenothiazine compound and D2DR inhibitor. Promazine Hydrochloride has been employed in studies investigating dopamine-stimulated glycosylation of brain proteins in vitro. It has actions similar to chlorpromazine but with less antipsychotic activity. It is primarily used in short-term treatment of disturbed behavior and as an antiemetic. Promazine hydrochloride blocks postsynaptic dopamine receptors D1 and D2 in the mesolimbic and medullary chemoreceptor trigger zone, thereby decreasing stimulation of the vomiting center in the brain and psychotic effects, such as hallucinations and delusions.

Progabide is an analog and prodrug of gamma-aminobutyric acid. It is commonly used in the treatment of epilepsy. It has agonistic activity for both the GABAA and GABAB receptors. Progabide has been investigated for many diseases besides epilepsy, including Parkinson's disease, schizophrenia, clinical depression and anxiety disorder with varying success.

Proflavine hemisulfate is an Acridine derivative, which is a slow-acting disinfectant with bacteriostatic action against many Gram-positive bacteria but less effective against Gram-negative organisms. Proflavine Hemisulfate has little antifungal activity.

Procyclidine hydrochloride is a muscarinic antagonist that crosses the blood-brain barrier and is used in the treatment of drug-induced extrapyramidal disorders and in Parkinsonism.

Procaterol hydrochloride is a specific and very potent β2-AR agonist. It acts as a vasodialator for long term treatment of asthma.

Procainamide hydrochloride is the hydrochloride salt preparation of Procainamide, a potent blocker of Na+ channels. Procainamide demonstrates antiarrhythmic effects correlated with blockade of the Na+ channels. Procainamide hydrochloride is an inhibitor of DNA methyltransferase.

Primaquine is an established antimalarial drug used in the treatment of persistent liver forms of P. vivax or P. ovale infection for its ability to kill late-stage gametocytes and hypnozoites. In historical terms, this aminoquinoline was the stimulus for the discovery of glucose-6-phosphate (G6P) dehydrogenase deficiency as it induced hemolytic anemia in patients lacking the G6P-metabolizing enzyme.

Priolocaine Hydrochloride is used as local nerve blocker and for spinal anesthesia. It is a local anesthetic of the amino amide type. Its pharmacological properties are similar to those of lidocaine.

Prednicarbate is a Corticosteroid. The mechanism of action of prednicarbate is as a Corticosteroid Hormone Receptor Agonist. Prednicarbate is a synthetic non-halogenated double-ester derivative of the corticosteroid prednisolone with anti-inflammatory, antipruritic and vasoconstrictive properties. This agent also decreases the number of circulating lymphocytes by suppression of the production of vasodilators such as prostacyclin and nitric oxide.

Pravastatin Sodium is an antilipemic fungal metabolite isolated from cultures of Nocardia autotrophica. It acts as a competitive inhibitor of HMG CoA reductase Pravastatin competitively inhibits hepatic hydroxymethyl-glutaryl coenzyme A reductase, the enzyme which catalyzes the conversion of HMG-CoA to mevalonate, a key step in cholesterol synthesis. This agent lowers plasma cholesterol and lipoprotein levels, and modulates immune responses by suppressing MHC II on interferon gamma-stimulated, antigen-presenting cells such as human vascular endothelial cells.

Practolol is a selective beta blocker that has been used in the emergency treatment of cardiac arrhythmias. Practolol is no longer used as it is highly toxic despite the similarity of its chemical formula to propranolol.

Pivampicillin Hydrochloride is the hydrochloride salt form of an orally active pivalate ester of ampicillin with antibacterial activity. Pivampicillin is hydrolyzed into its active form ampicillin by esterases. Ampicillin binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. Inactivation of PBPs interferes with the cross-linkage of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. This interrupts bacterial cell wall synthesis and results in the weakening of the bacterial cell wall, eventually causing cell lysis.

Pirbuterol Acetate is a short-acting β2 adrenoreceptor agonist with bronchodilating action used in the treatment of asthma as a breath-activated metered-dose inhaler.

Piperazine is an organic compound that consists of a six-membered ring containing two nitrogen atoms at opposite positions in the ring. Piperazine exists as small alkaline deliquescent crystals with a saline taste. Piperazine exists as small alkaline deliquescent crystals with a saline taste. Piperazine was introduced to medicine as a solvent for uric acid.

Piperacillin sodium is an antibiotic related to penicillin. Piperacillin binds to and inactivates penicillin-binding proteins (PBPs), enzymes located on the inner membrane of the bacterial cell wall, resulting in the weakening of the bacterial cell wall and cell lysis.

Pilocarpine hydrochloride is a slowly hydrolyzed muscarinic agonist with no nicotinic effects. Systemic administration of (+)-pilocarpine is typically used as an animal model for temporal lobe epilepsy and can mimic the generation of complex partial seizures by producing changes in hippocampal neuron morphology, membrane properties, and synaptic responses. Pilocarpine is used as a miotic and in the treatment of glaucoma.

Phensuximide is an anticonvulsant in the succinimide class. It suppresses the paroxysmal three cycle per second spike and wave EEG pattern associated with lapses of consciousness in petit mal seizures. The frequency of attacks is reduced by depression of nerve transmission in the motor cortex.

Perphenazine is a phenothiazine derivative and a dopamine antagonist with antiemetic and antipsychotic properties. Perphenazine blocks postsynaptic dopamine 2(D2) receptors in the mesolimbic and medullary chemoreceptor trigger zone (CTZ), thereby preventing the excess of dopamine in the brain. This leads to reduction in psychotic symptoms, such as hallucinations and delusions.

Permethrin is a widely-used pesticide of the pyrethroid family. Permethrin interacts with voltage-gated Na+ channels and inhibits their natural deactivation, causing the channels to remain open for a long time and destroying equilibrium of the neuronal system. Pyrethroids are also thought to interact with GABA receptors and associated pathways.

Pentamidine isethionate inhibits constitutive NOS1 in the brain and acts as a NMDA Glu antagonist. Pentamidine isethionate is an antimicrobial and neuroprotective agent.

Pentagastrin is a synthetic polypeptide that has effects like gastrin when given parenterally. It stimulates the secretion of gastric acid, pepsin, and intrinsic factor, and has been used as a diagnostic aid as the pentagastrin-stimulated calcitonin test. Pentagastrin binds to the cholecystokinin-B receptor, which is expressed widely in the brain. Activation of these receptors activates the phospholipase C second messenger system.

Penbutolol Sulfate is a medication in the class of beta blockers, used in the treatment of high blood pressure. Penbutolol is able to bind to both beta-1 adrenergic receptors and beta-2 adrenergic receptors, thus making it a non-selective β blocker. Penbutolol is a sympathomimetic drug with properties allowing it to act as a partial agonist at β adrenergic receptors. Penbutolol has also been found to be one of very few compounds that are 5-HT1A antagonists. 5-HT1A receptors are activated by serotonin, which have many different actions in different species. This makes it difficult to create generalizations about serotonin and its effects.

Pefloxacin mesylate dihydrate is a synthetic broad-spectrum fluoroquinolone antibacterial agent active against most gram-negative and gram-positive bacteria.